There is a huge gulf between using alcohol and becoming alcoholic. If he was the latter, we would know about it. Assuming, for arguments sake that we are looking at a Functioning Alcoholic. The man cannot buy a candle without the fact being recorded somewhere online. His dress, manner, and smell written down for posterity. In interviews he has become the subject of observational scrutiny beyond the norm. Do you really think up until now he has got away with it, and if it wasn't for the pesky kids on Solo ...?
The Guardian Roadie piece brought to our attention an event where the writer, who was new to the entourage, was encouraged to engage in an alcoholic binge ritual. I read it at the time as a bit of a masculine ice breaker. And let's not forget, this article was written in response to rejection from the tour. So, if Morrissey had a drink problem, then surely when on the subject of drinking with him, this would have been exposed. It wasn't.
As for Gallaghers latest comment. He is prone to talk in rather exaggerated terms. As a Mancunian who grew up in the shaddow of The Smiths, he would have been aware of the man who had lived a few streets from himself, with a fondness for tea and literature. So here he is, watching that same man pouring himself an over generous drink. So what?